DS1747P-70IND

Real Time Clock Overview

The DS1747P-70IND is a Y2K-compliant, nonvolatile timekeeping RAM module manufactured by Analog Devices Inc./Maxim Integrated. It integrates a 512k x 8 static RAM with a real-time clock (RTC), crystal oscillator, power-fail control circuit, and lithium energy source within a single component. The device utilizes a parallel interface with standard JEDEC byte-wide pinout for the SRAM portion, while RTC registers are mapped to the eight topmost memory locations. Operating at a nominal 5.0V supply, it supports an industrial temperature range of -40°C to +85°C.

Real Time Clock Feature Summary

• Integrated NV SRAM, RTC, Crystal, Power-Fail Control Circuit, and Lithium Energy Source
• Y2K Compliant with Automatic Leap Year Compensation Valid Up to the Year 2100
• Totally Nonvolatile with Over 10 Years of Operation in the Absence of Power
• BCD-Coded Century, Year, Month, Date, Day, Hours, Minutes, and Seconds

Real Time Clock Applications

• Industrial systems requiring precise timekeeping and data retention during power outages
• Embedded controllers needing integrated nonvolatile storage and calendar functions
• Equipment designed for harsh environments operating between -40°C and +85°C

Real Time Clock Procurement Notes

Verify that the specific order includes the separate PowerCap module (DS9034PCX+ or DS9034I-PCX+), as the DS1747P-70IND package requires this external component for battery and crystal connection. Confirm the lead-free status indicated by the '+' suffix aligns with project requirements. Ensure the 34-pin PowerCap Module Board footprint matches the PCB design constraints.

Real Time Clock Selection Notes

Select the DS1747P-70IND when surface-mount assembly is preferred over through-hole DIP packaging. This variant allows the PowerCap containing the battery and crystal to be mounted after the reflow soldering process, protecting sensitive components from high temperatures. Choose this part if system design benefits from replacing the battery independently of the main IC.

Real Time Clock Part Context

The DS1747P-70IND belongs to the DS174x family of nonvolatile timekeeping RAMs. It is functionally similar to the DS1747-70IND but differs in physical packaging. While the DS1747-70IND encapsulates all components in a 32-pin EDIP, the DS1747P-70IND uses a 34-pin PowerCap Module Board design intended for surface mount applications with an externally attached PowerCap.

Real Time Clock Replacement Considerations

Direct pin-for-pin compatible replacements within the same density include other DS1747 variants such as the commercial grade DS1747P-70+. For different densities, the DS1746 series offers compatibility but with varying storage capacities.